The present application relates to a trigger switch circuit mounted on an electric instrument or appliance, such as an electric drill.
Electrical appliances or electrical instruments commonly have a trigger switch circuit attached to the trigger, and the trigger switch is used primarily to turn on or off operation of a motor in the electrical appliance or instrument. Recently, in order to increase convenience for a user, a trigger switch device that turns on or off a light-emitting element for illumination when actuated has also been considered, and has been described, for example, in United States Patent Publication No. 2006/0186102 (published on Aug. 24, 2006), which is incorporated herein by reference in its entirety.
In conventional electric instruments which use a trigger switch device and comprise a light-emitting element, when the electric instrument is used, before operating the motor, surroundings may be illuminated and checked. However, in the conventional trigger switch circuit when the light-emitting element 15 emits light, electric power is also supplied to an integrated circuit IC made of a control unit and an operational amplifier, which controls the rotational speed of the motor. Thus, in the case where illumination is performed without operating the motor, electric power is also supplied to the circuits related to the motor, causing wasteful power consumption.
In order to avoid this problem, a switch may be newly provided to turn on and off the supply of electric power to the integrated circuit IC, however, this would increase the number of components in the trigger device.